云南孟定盆地1961—2008年蒸发量变化特征分析

An analysis of evaporation variation from 1961 to 2008 of Mengding Basin in Yunnan Province

采用线性趋势法、Mann-Kendall检验法、相关系数法等对孟定盆地48 a来蒸发量变化特征进行分析。结果表明,蒸发量减少趋势十分显著,倾向率为-31.35 mm/10 a,48 a来减少了150.5 mm。其中,雨季减少速率最大,为-26.6 mm/10a,春季其次,倾向率为-20.8 mm/10 a;年蒸发量10a、冬季9a、干季10 a的变化周期十分显著;除冬季呈微弱的突变增加外,年和各季均突破-1.96(α=0.05)的临界线,突变减少趋势十分显著;日照时数的显著减少和相对湿度的增加是蒸发量减少的重要原因。

The linear regression method, Mann-Kendall test method, correlation coefficient method, and mean generating function model are employed to analyze the evaporation variation of Mengding Basin in the past 48 years. The results show that the evaporation decrease trend is very significant and it decreased 150.5 mm in the past 48 years, and the changed rate is - 31.35mm/lOa. Among the four seasons, the biggest decrease rate is the rainy season, which is -26.6 mm/10a, only next to that of spring, namely, -20.8 mm/10a. The annual,winter and dry season evaporation has a 10-year,9-year and 10-year varia- tion cycle respectively. Apart from the fact that the winter evaporation has a slight mutation increase, the mutation decrease trend is significant, which breaks the borderline -1.96 （a = 0.05 ）, correlation coeffi- cient method and the grey correlation analysis show that the sunshine duration significantly reduced and the increase of relative humidity is the important reasons for vaporization.